Apple Pay is paying stuff without my permission

Yesterday my brother had sent me 5 dollars because I did him a favor and literally I wake up today… why is there a purchase on my Apple Pay already? It’s a purchase I’ve never even made before. Literally I tried finding out what it was and appearently it was this editing app that I had that I was trying out the free trial for. Why did it already pay 5 dollars when I didn’t give it permission to. I just wanted to try out the app not pay for it already as soon as it ended?? Please do better Apple. I really need those 5 bucks back. Thank you.